• Journal of Korean Society on Water Environment
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• v.37 no.4
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• pp.249-262
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• 2021

This study investigated the pollution characteristics of the main pollution zone in the Hwangguji watershed and the influence of the tributary on the main stream. The characteristics of the main pollution zone, including, the water quality index (WQI), stream rating, load duration curve (LDC), delivery load density (DLD), and contribution of the tributary to the mainstream, were evaluated by time-series visual heatmap. The WQI of the mainstream of Hwangguji was lowered to the poor (IV) level from the inflow point of Suwon stream (SW) and the LDC excess rate in the T-P was higher than that of BOD₅, especially for the wet season, suggesting that management of non-point source with T-P is preferred. The contribution (%) of the tributaries in the upstream section of Hwangguji watershed were BOD₅ 14.54%, TOC 15.67%, T-N 5.43%, and T-P 6.97%. In particular, the Suwon sewage treatment plant located in the mainstream showed a high contribution of BOD₅ (64.40%) and T-P (53.54%), respectively, due to the high discharge rate (6.019 m³/sec). Meanwhile, Sammi and Gal stream have a large impact on the mainstream with high DLD and poor WQI. Thus, both streams were considered as pollution hot spots. These results provide useful basic data for preparing more effective water quality improvement and management plans in the watershed.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.455-467
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• 2021

Macrofungi are valuable resources as novel drug candidates, new biomaterials, and edible materials. Recently, genetic approaches pertaining to macrofungi have been continuously growing for their identification, molecular breeding, and genetic engineering. However, purification and amplification of fungal DNA is challenging because of the rigid cell wall and presence of PCR inhibitory metabolites. Here, we established a direct PCR method to provide a rapid and efficient method for PCR-grade macrofungal DNA preparation applicable to both conventional PCR and real-time PCR. We first optimized the procedure of lysis and PCR using the mycelia of Lentinula edodes, one of the most widely consumed macrofungal species. Lysates prepared by neutralizing with (NH₄)₂SO₄ after heating the mycelia in a mixture of TE buffer and KOH at 65℃ for 10 min showed successful amplification in both conventional and real-time PCR. Moreover, the addition of bovine serum albumin to the PCR mixture enhanced the amplification in conventional PCR. Using this method, we successfully amplified not only internal transcribed spacer fragments but also low-copy genes ranging in length from 500 to 3,000 bp. Next, we applied this method to 62 different species (54 genera) of macrofungi, including edible mushrooms, such as Pleurotus ostreatus, and medicinal mushrooms such as Cordyceps militaris. It was found that our method is widely applicable to both ascomycetes and basidiomycetes. We expect that our method will contribute to accelerating PCR-based approaches, such as molecular identification, DNA marker typing, gene cloning, and transformant screening, in macrofungal studies.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.283-288
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• 2008

Eight subprimal cuts purchased from the branded Hanwoo beef of 3 quality grades ($1^{++}$, $1^+$, 1) at 13 stores were evaluated the tenderness using Warner-Bratzler shear (WBS). The beef frequency ratio (%) depending on postmortem aging periods were investigated. The 37.5 (quality grade $1^{++}$), 45.8 (quality grade $1^+$), and 36.4% (quality grade $1^{++}$) of branded beef were aged for < 7 d, 26.6 (quality grade $1^{++}$), 47.2 (quality grade $1^+$) and 36.4% (quality grade 1) were aged for $7{\sim}13$ d, and 31.3 (quality grade $1^+$), 4.2 (quality grade $1^+$) and 25.8% (quality grade $1^+$) were aged for 14 to 20 d. The temperature of cold room in stores was ranged average 2.27 to $2.42^{\circ}C$. WBS values for ansimsal (tenderloin), witdngsimsal (ribeye), cheggtsal (shortloin), doganisal (knuckle) and moongchisatae (hind shank) from branded Hanwoo beef of quality grade $1^{++}$ were tender than those from branded Hanwoo beef of quality grade 1 (p<0.05). WBS values for ansimsal (tenderloin) were 2.56 (quality grade $1^{++}$), 2.76 (quality grade $1^+$) and 3.10 kg (quality grade 1), respectively, and those for doganisal (knuckle, quality grade $1^{++}$), hongdukesal (eye of round, quality grade $1^+$) and bosupsal (top sirloin, quality grade 1) were 4.76, 4.96 and 5.66kg, respectively (p<0.05). The frequency ratio (%) of WBS < 3.9 kg in the all subprimal cuts from branded Hanwoo beef of quality grade $1^{++}$ were 100 [ansimsal (tenderloin) and cheggtsal (shortloin)], 87.5 [witdngsimsal (ribeye)] and 62.5% [bosupsal (top sirloin)], whereas that of WBS > 4.6 kg were 50.0% [hongdukesal (eye of round) and doganisal (knuckle)]. The frequency ratio of WBS < 3.9 kg in the an subprimal cuts of quality grade $1^+$ were 100 [ansimsal (tenderloin) and witdngsimsal (ribeye)] and 44.4% [cheggtsal (shortloin) and gurisal (chuck tender)], whereas that of WBS > 4.6 kg were 66.7 [hongdukesal (eye of round)], 55.6 [doganisal (knuckle)] and 44.4% [bosupsal (top sirloin)]. The frequency ratio (%) of WBS < 3.9 kg in the all subprimal cuts of quality grade 1 were 88.9 [ansimsal (tenderloin)], 62.5 [cheggtsal (shortloin)] and 44.4% [witdngsimsal (ribeye)], whereas that of WBS > 4.6 kg were 100.0 [doganisal (knuckle)] 62.7 [hongdukesal (eye of round)], 62.5 [gurisal (chuck tender)] and 55.6% [moongchisatae (hind shank)]. From these results, subprimal cuts from branded Hanwoo beef were marketed with short aging periods and high frequency ratio (%) of WBS > 4.6 kg.

• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.415-426
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• 2014

This study aimed to investigate the effects of Cornell typed science journal writing on elementary students' science-related attitude by gender and academic achievement. The subjects of study were 109 elementary students (5th grade). The experimental group performed Cornell typed science journal writing and the control group maintained traditional lectures for one semester. Science-related attitudes of this study are classified into scientific attitudes (7 sub-domains) and attitudes toward science (5 sub-domains). The collected data were analyzed by ANCOVA with SPSS. The results of study were as follows: Several sub-domain (voluntariness, cooperation, perception about science and scientist) of science-related attitudes positively changed in experimental group. Cornell typed science journal writing was especially effective on improving scientific attitude in male students, and attitude toward science in female students. Also, science journal writing was effective on improving science-related attitude (both scientific attitude and attitude toward science) in high-achieving group, but not effective in low-achieving group.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.6
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• pp.670-682
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• 2018

This paper presents the experimental and numerical investigation results of the response of low-temperature steel (LT-FH32 grade steel) beams under repeated impacts at room temperature and a single impact at a sub-zero temperature. After conducting tensile tests at room and sub-zero, repeated impact tests were conducted on two clamped single-beam models at room temperature, and single-impact tests of two other clamped single-beam models were conducted at $-50^{\circ}C$. The single and repeated impact tests were conducted by releasing a knife-edge striker using a drop testing machine. The permanent deflection of the model measured after each impact gradually increased with increasing number of impacts. Under the reduced temperature, the permanent deflection of the models slightly decreased. The numerical analyses were also performed to predict the damage response of the tested single-beam models. A comparison of the numerical prediction with those of experiments showed quite reasonable agreement.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.171-182
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• 2022

In this study, by classifying latent groups for disaster safety awareness focusing on the four sub-factors of the developed disaster awareness scale of high school students, the characteristics of each group were examined, and the differences between latent classes according to inter-individual differences were investigated. As a result of analysis based on the data of a total of 1054 high school students, the disaster safety awareness of high school students was classified into three latent groups. Each latent group was named 'High Safety Awareness Type(SAT)', 'Normal SAT', and 'Low SAT' according to its characteristics. In all four fire safety awareness sub-factors, 'High SAT', which had a high score, accounted for 56.5% of the total, and 'Normal SAT', which had a moderate score in the sub-factors, had the lowest ratio at 20.3%. There were no significant differences by gender, grade, and academic achievement of the latent group. These results are not only meaningful as the first study of the latent profile analysis of high school students on disaster safety awareness, but also help to identify the characteristics of individuals in each latent group with more subdivisions and provide useful data for disaster safety awareness education according to individual differences. The implications of this study and suggestions for follow-up studies were discussed.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.366-374
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• 2015

Herein, we established a repeated-batch process for ethanol production from glycerol by immobilized Pachysolen tannophilus. The aim of this study was to develop a more practical and applicable ethanol production process for biofuel. In particular, using industrial-grade medium ingredients, the microaeration rate was optimized for maximization of the ethanol production, and the relevant metabolic parameters were then analyzed. The microaeration rate of 0.11 vvm, which is far lower than those occurring in a shaking flask culture, was found to be the optimal value for ethanol production from glycerol. In addition, it was found that, among those tested, Celite was a more appropriate carrier for the immobilization of P. tannophilus to induce production of ethanol from glycerol. Finally, through a repeated-batch culture, the ethanol yield (Y_e/g) of 0.126 ± 0.017 g-ethanol/g-glycerol (n = 4) was obtained, and this value was remarkably comparable with a previous report. In the future, it is expected that the results of this study will be applied for the development of a more practical and profitable long-term ethanol production process, thanks to the industrial-grade medium preparation, simple immobilization method, and easy repeated-batch operation.

• Corrosion Science and Technology
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• v.17 no.3
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• pp.109-115
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• 2018

Electrical Resistance Welding (ERW) on a longitudinal seam-welded pipe has been extensively used in oil and gas pipelines. It is well known that the weld zone commonly suffers from grooving corrosion in ERW pipes. In this paper, the grooving corrosion performances of API X65 grade non-sour service (steel-A) and API X70 grade sour gas resistant (steel-B) steel electrical resistance welding pipelines were evaluated. The microstructure of the bondline is composed of coarse polygonal ferrite grains and several elongated pearlites. The elongated pattern is mainly concentrated in the center of the welded area. The grooving corrosion test and electrochemical polarization test were conducted to study the corrosion behavior of the given materials. A V-shaped corrosion groove was found at the center of the fusion zone in both the steel-A and steel-B ERW pipes, as the corrosion rate of the bondlines is higher than that of the base metal. Furthermore, the higher volume fraction of pearlite at the bondline was responsible for the higher corrosion rate at the bondline of both types of steel.

• Fashion & Textile Research Journal
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• v.7 no.3
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• pp.291-300
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• 2005

The purpose of this study is to investigate, analyze the purchasing behavior of fashion goods according to life style and role model of preteen generation, and provide manager or marketing planner for the reference data so that they can understand preteen generation and make proper strategy efficiently. So called, preteen market focusing on 1014 generation (from ten to fourteen years old) is highlighted. This generation created between the year 1989 to 1993 after Seoul Olympic monopolize parent's love in abundant economic environment and rise to the core of consumption subject. Products aiming at this preteen generation continuously though consumption mind was shrunk greatly due to recession. Only 2~3 years before preteen market was regarded as grey zone which doesn't belong to not only children (between six and nine years old) but also teenagers (between fifteen to eighteen years old). But in recent day their purchasing powers have increased rapidly and age group is divided on details, so that preteen market has become a niche market. Subjects were 333 persons consisting of students in the 4th~6th grade of primary school and the 1st~2nd grade of middle school in Daegu city. Measuring instruments are as follows: 5questions to differentiate preteen generation, 22 questions to measure life style, 17questions (which have six sub-factors such as purchase motive, factor of product selection, utilization of informant, purchase time, purchase place, and purchase method) to measure the purchase behavior of fashion goods measurement, and 16 questions (which have four sub-factors such as parent, entertainer & sports stars, brothers and sisters, friends) to measure model of role. Statistical data were processed by SPSS 10.0 programs. Frequencies, Factor analysis, Cluster analysis, ANOVA, Cross analysis, Multiplex regression analysis, and Duncan's multiple range test were carried out.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.171-176
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• 2019

The objective of this study was to investigate the effect of undergraduates' self-directed learning on the school life satisfaction and interpersonal relation ability. For this purpose, 341 undergraduates were targeted and analyzed. The results of the study are as follows. First, as a result of analyzing school life satisfaction, a sub-factor of self-directed learning, all of gender, grade, and age affected. In addition, sub-factors such as study confidence, study passion, study responsibility seemed to affect positively significantly in order. Second, as a result of analyzing the effect on interpersonal relation skills of self-directed study, there was no significant relation in gender, grade, and age. Based on the results of this study, it was confirmed that school life satisfaction and interpersonal relation abilities are closely related to self-directed learning. This is significant in that to revitalize institutions such as educational service, study support for students, self-directed learning programs development in education field at the university, etc. are required.